Field of the Invention
This invention relates to a seal ring for vehicles used for a vehicle transmission and so on.
Description of the Related Art
Conventionally, various seal rings for sealing an annular gap between a rotating shaft and a housing have been proposed. For example, International Publication No. 2003/078873 (WO2003/078873A) describes a seal ring of substantially rectangular cross-sectional shape adapted to enhance sealing performance at a single incision in the circumferential direction. The seal ring described in WO2003/078873A is accommodated in an annular groove formed in the outer peripheral surface of the rotating shaft and a side surface of the seal ring is pushed against a side surface of the annular groove by the pressure of oil in a sealed space, thereby preventing leaking of oil.
However, when no oil pressure acts on the sealed space, such as when an associated engine stops, any axial direction movement of the rotating shaft relative to the housing allows a gap to form between the side surface of the housing and the side surface of the seal ring, so that oil is apt to flow out of the sealed space through the gap.